local LEVEL_LOWER = 1
local LEVEL_SAME = 2
local LEVEL_HIGHER = 3

local DISTANCE_BESIDE = 1
local DISTANCE_CLOSE = 2
local DISTANCE_FAR = 3
local DISTANCE_VERYFAR = 4

local directions = {
	[DIRECTION_NORTH] = "north",
	[DIRECTION_SOUTH] = "south",
	[DIRECTION_EAST] = "east",
	[DIRECTION_WEST] = "west",
	[DIRECTION_NORTHEAST] = "north-east",
	[DIRECTION_NORTHWEST] = "north-west",
	[DIRECTION_SOUTHEAST] = "south-east",
	[DIRECTION_SOUTHWEST] = "south-west"
}

local messages = {
	[DISTANCE_BESIDE] = {
		[LEVEL_LOWER] = "is below you",
		[LEVEL_SAME] = "is standing next to you",
		[LEVEL_HIGHER] = "is above you"
	},
	[DISTANCE_CLOSE] = {
		[LEVEL_LOWER] = "is on a lower level to the",
		[LEVEL_SAME] = "is to the",
		[LEVEL_HIGHER] = "is on a higher level to the"
	},
	[DISTANCE_FAR] = "is far to the",
	[DISTANCE_VERYFAR] = "is very far to the"
}

local spell = Spell("instant")

function spell.onCastSpell(creature, variant)
	local targetId = ForgeMonster:pickClosestFiendish(creature)
	if not targetId then
		creature:sendCancelMessage("No creatures around")
		creature:getPosition():sendMagicEffect(CONST_ME_POFF)
		return false
	end
	local target = Creature(targetId)
	if not target then
		creature:sendCancelMessage("No creatures around")
		creature:getPosition():sendMagicEffect(CONST_ME_POFF)
		return false
	end

	local targetPosition = target:getPosition()
	local creaturePosition = creature:getPosition()
	local positionDifference = {
		x = creaturePosition.x - targetPosition.x,
		y = creaturePosition.y - targetPosition.y,
		z = creaturePosition.z - targetPosition.z
	}

	local maxPositionDifference, direction = math.max(math.abs(positionDifference.x), math.abs(positionDifference.y))
	if maxPositionDifference >= 5 then
		local positionTangent = positionDifference.x ~= 0 and positionDifference.y / positionDifference.x or 10
		if math.abs(positionTangent) < 0.4142 then
			direction = positionDifference.x > 0 and DIRECTION_WEST or DIRECTION_EAST
		elseif math.abs(positionTangent) < 2.4142 then
			direction = positionTangent > 0 and
							(positionDifference.y > 0 and DIRECTION_NORTHWEST or DIRECTION_SOUTHEAST) or
							positionDifference.x > 0 and DIRECTION_SOUTHWEST or DIRECTION_NORTHEAST
		else
			direction = positionDifference.y > 0 and DIRECTION_NORTH or DIRECTION_SOUTH
		end
	end

	local level = positionDifference.z > 0 and LEVEL_HIGHER or positionDifference.z < 0 and LEVEL_LOWER or LEVEL_SAME
	local distance = maxPositionDifference < 5 and DISTANCE_BESIDE or maxPositionDifference < 101 and DISTANCE_CLOSE or
						 maxPositionDifference < 275 and DISTANCE_FAR or DISTANCE_VERYFAR
	local message = messages[distance][level] or messages[distance]
	if distance ~= DISTANCE_BESIDE then
		message = message .. " " .. directions[direction]
	end

	local monsterType = target:getType()
	local stringLevel = 'Unknown'
	if monsterType and creature:isMonsterBestiaryUnlocked(monsterType:raceId()) then
		local bestiaryKillsAmount = monsterType:BestiarytoKill()
		if bestiaryKillsAmount >= 5 and bestiaryKillsAmount <= 25 then
			stringLevel = 'Harmless'
		elseif bestiaryKillsAmount <= 250 then
			stringLevel = 'Trivial'
		elseif bestiaryKillsAmount <= 500 then
			stringLevel = 'Easy'
		elseif bestiaryKillsAmount <= 1000 then
			stringLevel = 'Medium'
		elseif bestiaryKillsAmount <= 2500 then
			stringLevel = 'Hard'
		elseif bestiaryKillsAmount <= 5000 then
			stringLevel = 'Challenging'
		end
	end

	message = string.format("The monster " .. message .. ". Be prepared to find a creature of difficulty level \"" ..
								stringLevel .. "\".")
	local timeLeft = math.floor((target:getTimeToChangeFiendish() - os.time()) / 60)
	if (timeLeft < 15) then
		message = string.format(message .. " " .. ForgeMonster:getTimeLeftToChangeMonster(target))
	end

	creature:sendTextMessage(MESSAGE_INFO_DESCR, message)
	creaturePosition:sendMagicEffect(CONST_ME_MAGIC_BLUE)
	return true
end

spell:name("Find Fiend")
spell:words("exiva moe res")
spell:group("support")
spell:vocation("druid;true", "elder druid;true", "knight;true", "elite knight;true", "paladin;true",
	"royal paladin;true", "sorcerer;true", "master sorcerer;true")
spell:id(20)
spell:cooldown(2 * 1000)
spell:groupCooldown(2 * 1000)
spell:level(25)
spell:mana(20)
spell:isAggressive(false)
spell:needLearn(false)
spell:register()
